The present invention relates to a pneumatic tire having an improved tread pattern.
In order to improve the aquaplaning resistance of a pneumatic tire, widely employed techniques for increasing the drainage of tread grooves are: to increase the number of the tread grooves, to increase the width of a tread groove and/or to increase the depth of a tread groove. Such techniques however have disadvantages such that the tread pattern rigidity is decreased, the steering stability on dry roads is deteriorated, and the noise performance is deteriorated.
US Patent Application Publication No. 2006-137791A1 discloses a tread pattern shown in FIG. 10, wherein a central rib c1 and middle ribs c2 extend continuously in the circumferential direction to improve the steering stability, oblique grooves (e) disposed in the middle ribs c2 are connected to shoulder circumferential grooves b2 to improve the drainage, and the oblique grooves (e) are not connected to crown circumferential grooves b1 to block air column resonance sound possibly occurring in the crown circumferential grooves b1. In such a tire, however, further improvement is demanded about the noise performance, the steering stability, ride comfort and aquaplaning resistance.